Loading terminal for tankers or other large ships with flowable cargo

ABSTRACT

An offshore mooring terminal for transferring liquid or flowable cargo between a ship and an onshore station. The ship is connected to the mooring terminal by a single mooring line connected at one end to a swiveling anchor located at the sea bottom. A buoyant riser column is attached at its lower end to the anchor by an articulate joint which permits the riser column to pitch and roll with the waves. The upper end of the riser column extends above or near the surface of the sea. The riser column provides a conduit for the fluid and includes a rotary joint at its upper end to receive the floating hoses running to the ship, and a connection to a submarine pipeline at its lower end for carrying the fluid shoreward or to other destinations as may be required. The swiveling anchor device to which the mooring line is secured allows the ship to rotate about the mooring terminal as it swings in the current.

1J1 States Patent 1 Adler et al.

[4 1 Sept. 4, 1973 [75 Inventors: Cyrus Adler, New York, N.Y.;

Lewis Schneider, Springfield, NJ

[73] Assigneez Cyrus Adler, NEWYMKJITYJ' 22 Filed: Feb. 20, 1970 21Appl. No.: 12,995

[52] US. Cl 141/388, 61/46, 137/236, 141/279 [51] Int. Cl B65b l/04 [58]Field of Search 141/387, 388, 279, 141/284; 137/236, 615; 9/8; 114/05;166/05; 61/46 [56] References Cited UNITED STATES PATENTS 3,311,1423/1967 Bergstrom 141/388 3,366,088 1/1968 Gibson 114/0.5 3,407,416 10/1968 Brickhouse 9/8 3,434,442 3/ 1969 Manning 114/05 3,472,032 10/1969Howard 61/46 3,515,182 '6/1970 Dickson et a1... 141/388 3,568,737 3/1971Burns 141/388 3,372,409 3/1968 Manning 137/236 3,519,034 7/1970 Manning137/236 3,519,036 7/1970 Manning 137/236 3,535,883 10/1970 Manning137/236 1 Primary Examiner-Bell, Jr., Houston S.

Attorney-Ryder, McAulay & Hefter [5 7 ABSTRACT An offshore mooringterminal for transferring liquid or flowable cargo between a ship and anonshore station. The ship is connected to the mooring terminal by asingle mooring line connected at one end to a swiveling anchor locatedat the sea bottom. A buoyant riser column is attached at its lower endto the anchor by an articulate joint which permits the riser column topitch and roll with the waves. The upper end of the riser column extendsabove or near the surface of the sea. The riser column provides aconduit for the fluid and includes a rotary joint at its upper end toreceive the floating hoses running to the ship, and a connection to asubmarine pipeline at its lower end for carrying the fluid shoreward orto other destinations as may be required. The swiveling anchor device towhich the mooring line is secured allows the ship to rotate about themooring terminal as it swings in the current.

20 Claims, 8 Drawing Figures mamas" 4m 3.756293 SHEEI'I 0F 5 I FIG! 50J'Qgfl a CYRUS ADLER LEWIS SCHNEIDER INVENTORS 14 T 7 OANE X9 'PATENTEDW4 ma CYRUS ADLER LEWIS SCHNEIDER IN VENTORS VPATENTEBSEP 4 ms SHEEI 3 0F5 PATENTEDSEP 41915 3.756293 H65 sumuurs @"j FIG-Z CYRUS ADLER' LEWISSCHNEIDER INVENTORB 4rToRA/E Y5 PATENTEDSEP 4m 3.756293 sum 5 or 5 CYRUSADLER LEWIS SCHNEIDER ATTORA/IEXS INVENTORS LOADING TERMINAL FOR TANKERSOR OTHER LARGE SHIPS WITH FLOWABLE CARGO BACKGROUND OF THE INVENTION 1.Field of the Invention This invention relates to an offshore mooringterminal, and more particularly to a single point mooring terminal forthe loading or discharge of liquid or flowable cargo onto or fromtankers or other large ships.

2. Description of the Prior Art Economic factors in industries, such asthe petroleum industry, combined with the geographic disposition ofpetroleum resources and world markets have led to the increasedutilization of very large tankers for the transportation of crudepetroleum and products. The unavailability of harbors with sufficientdraft or berthing facilities to allow entry of such large ships at thecrude oil sources andreflnery and market locations has led to the use ofoffshore terminals.

One conventional approach to such a terminal is the single point mooringbuoy whereby the ship is connected to an anchored floating buoy by a bowhawser. The hawser anchorage is free to swivel on the buoy in a mannerwhich permits the ship to rotate about the buoy and generally facebow-on to the wind and current, thus tending to minimize the mooringforces on the anchorage. The system includes a length of floating hosebetween the-ship and buoy, and a flexible hose connected between thebuoy and the submarine pipe line running to the shore. A rotary fluidjoint is provided on the top of the buoy to allow the floating hose toswivel in response to the movement of the ship as it swings about themooring point. Also, the lower portion of the buoy is connected to thebuoy anchorage by means of a plurality of long chains extending to thesea bottom.

The above-described prior art system is large and expensive. A principaldisadvantage is that the large dynamic forces acting on the ship fromthe action of wind, wave and current are directly transmitted to thebuoy by the mooring line attached to the top of the buoy. In turn, abuoy of substantial size is required to accommodate these large forcesand the buoy must be constrained by large anchor chains. Furthermore,the static buoyancy of the buoy is relatively great, so that the chainsare constantly subjected to high tension whether a ship is moored ornot; resulting in abrasive wear on the chain lengths as the buoyresponds to wave action. Since the cost of the chain is a large percent(in the order of one-third) of the total initial cost of theconventional buoy system, such abrasive action necessitating replacementof the chain can produce a substantial addition to life cycle costs.

Also, in the prior art mooring system referred to above where aplurality of chains connect a mooring tower or buoy to the anchors, themooring tower or buoy is held relatively rigid, thereby permitting verylittle roll of the buoy in response to wind, waves and currents. Such arigid connection of the buoy creates high stresses in the buoy and thesupporting anchor chains, since the'buoy is unable to substantiallycomply and roll with the waves and currents. In addition, in mostmooring systems flexible hosesare employed to connect the submarinepipeline near the bottom of the sea in fluid communication with thefluid conduit connectors at the bottom of the buoy. Consequently, alarge degree of twisting movement of the buoy will unduly stress thehoses, often requiring replacement by procedures which are bothtime-consuming and expensive.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide a single point mooring terminal which substantially eliminatesthe large dynamic forces ordinarily transmitted from a ship to a mooringbuoy.

It is another object to provide a mooring terminal having structuralelements which are relatively small in size and weight and yet has ahigh structural efficiency in accommodating the dynamic forces acting ona ship from the action of wind, wave and current.

It is another object to provide a mooring terminal which is relativelysmall in size and develops relatively small static buoyancy forces, sothat the anchor means for the mooring terminal are not constantlysubject to high static tension forces.

It is another object of the invention to provide a mooring terminalwhich is relatively small in size, does not require frequent replacementof parts, and is easily maintainable.

It'is another object to provide a mooring terminal in which the buoymember readily complies and rolls with the waves and currents withoutdeveloping high stresses on the mooring terminal.

It is still another object to provide a mooring terminal in which thebuoy member readily complies and rolls upon accidental collisions orbumping by sea vessels, without damage to the mooring terminal.

It is a further object to. provide a mooring terminal which does notpermit a significant twisting movement of the buoy member.

These and other objects, which will become apparent from the detaileddisclosure and claims to follow are achieved by the present inventionwhich provides a single point mooring terminal for transferring fluidbetween a ship and an onshore station. The ship is connected to themooring terminal by a mooring line anchored directly to the foundationthrough a swivel connection on the anchor located at the sea bottom. Abuoyant riser column extends substantially from above the surface of thesea down to the anchor to which it is connected by an articulate joint.The riser column provides a conduit for the fluid and includes a rotaryjoint at its upper end to receive the floating hoses running to theship, and a fluid coupling to a submarine pipe line at its lower end.The swivel connection between the mooring line and the anchor allows theship to rotate about the mooring terminal. Also, the articulate jointpermits the riser column to pitch and roll with the waves and currentswhile preventing any significant twisting movement of the riser column.

- In one modification, a rigid boom structure is confluid" is intendedto mean any liquid, gas or fluid slurry with solid particles suspendedtherein.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view of themooring terminal connected to a ship, illustrative of the invention;

FIGS. 2, 3 and 4, respectively, are front, side and perspective views ofthe articulate joint employed in the mooring terminal shown in FIG. 1;

FIG. 5 shows a detailed cross-sectional view of the swivel connectionbetween the mooring line and the anchor;

FIG. 6 is a side elevation view of the mooring terminal connected to aship, illustrating a modification incorporating the rigid boomstructure;

FIG. 7 is a plan view of the system shown in FIG. 6; and

FIG. 8 is a side elevation view of the mooring terminal shown in FIG. 6,in the position it assumes when a ship is not connected to the mooringline or under light current conditions.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, there isshown the single point mooring terminal 10 of the invention connected toa ship 12 located offshore in a sea 14. Mooring terminal 10 generallyincludes a mooring chain or line 16 connected at its lower end 18 to aswivel connection 20 on the anchor 22 located at the sea bottom 24. Theupper end 26 of the mooring line 16 is connected to an auxiliaryfloating buoy 28 by means of a fitting 30 provided on such buoy 28. Whena ship is not anchored or moored to the mooring terminal 10, theauxiliary buoy 28 maintains the upper end 26 of line 16 at the seasurface 32, so as to be readily accessible for connection to a shipshawser 34. Mooring terminal 10 also includes a riser column 36 attachedat its lower end to the anchor 22 by an articulate joint 38. The upperend of riser column 36 extends above the sea surface 32 to a point wherea horizontal rotary swivel joint 40 connects a floating hose 42 to themanifold of the swivel joint 40. Also, a vertical swivel joint 41permits free rotation of the hose 42 about the vertical axis of theriser column 36.

The riser column 36 is a substantially rigid member, made of a material,such as steel, which provides a conduit for the fluid via one or morepipes, not shown, extending throughout its length. Riser column 36preferably has a cylindrically shaped external surface in order tomaintain the drag forces at a minimum, while it may internally compriseeither one pipe, a cluster of parallel pipes or coaxial pipes dependingon the specific requirements. A buoyancy chamber 44 is provided for theriser column 36 and designed to maintain the riser column 36 in a stateof positive buoyancy at all times so that the riser column 36 tends toremain in an essentially upright position under the action of seacurrents and waves. Buoyancy chamber 44 can, for example, be designed tolimit the pitch and roll angle of the riser column 36 to degrees. Ifdesired, a floating ring buoy 47 can be connected so as to extend aroundthe upper end of the riser column 36. The floating ring buoy 47 acts asa fender to protect the riser column 36 from small craft and debris, andalso serves as a working platform and a support for the inboard end ofthe floating hose 42.

Fluid is transferred from a ship tank through the floating hose 42 tothe manifold of the rotary swivel joint 40 where it then passes downthrough the conduits in the riser column 36. It is noted that more thanone floating hose 42 can be employed, if desired. The lower end of theriser column 36 terminates in a Y feeding into two short flexible hoses46 and 48 which are thence connected in a second Y leading into asubmarine pipe line 50 at the sea bottom 24 for carrying the fluidshoreward or to other destinations as may be required. Of course, thefluid can be passed through the system in the opposite direction to thatdescribed above. It is to be pointed out that while this specificflexible hose arrangement is shown as the preferred embodiment, othersuitable hose arrangements can be employed.

The swivel connection 20 for the mooring line 18 generally comprises abearing ring around a vertical axis of rotation. In the specificembodiment shown, a ring girder 52 extends annularly around the lowerend of the mooring terminal 10 and is slidably mounted in a fixedbearing frame 54 attached to the anchor 22. Also, anchor 22 is shown asa large diameter caisson sunk into the sea bottom 24 sufficiently tosustain the shear and uplift forces on the anchor foundation 22.However, alternate arrangements not shown, using clusters of concretepipe or piles or drilled-in anchorages may be utilized depending on theactual sea bottom conditions at a particular site. As the direction ofthe wind and current varies, a tangential component of force will bedeveloped at the swivel connection 20 causing the ring girder 52 toswivel on its bearings about a vertical axis. This swivel movementallows the ship to rotate about the mooring terminal 10 as it swings inthe current. It is noted that the large dynamic forces acting on theship are not directly transmitted to the riser column 36 by the mooringline 16, since such mooring line 16 is not attached to the anchor 22through the riser column 36, but rather is directly attached via theswivel connection 20 to the anchor 22. Therefore, the articulated risercolumn 36 is subjected only to the forces acting upon itself and thefloating hose 42.

In this fashion, since the ship forces are carried directly to theanchor 22 rather than through an intermediary buoy structure such as theriser column 36, and since the large structure, in the form of the ringgirder 52 and mounting frame 54, is located at the sea bottom 24 ratherthan at the surface 32 where it would be subjected to the full intensityof wind and wave action, a great economy in the size and the weight ofthe required structural elements is achieved. Further details of theswivel connection 20 will be discussed hereinafter, in reference to FIG.5.

Referring to FIGS. 2, 3 and 4 are shown, respectively, the front, sideand perspective views of the articulate joint 38. Specifically, thelower end 56 of the riser column 36 is fitted with a pair of trunnions58 and 60 joining such riser column 36 to a chain linkage arrangementcomprising chain links 62-76. Upper chain links 62 and 64 form a swivelconnection with trunnion pin 58 and, similarly, upper chain links 66 and68 form a swivel connection with trunnion pin 60. The other ends of eachof chain links 62-68 are connected to the respective comers of a rigidframe structure 78. An additional pair of trunnion or hinge pins 80 and82 are fixedly attached to the frame structure 78, and provide theswivel pins for the lower chain links 70 and 72, and 74 and 76,respectively. The lower ends of each of chain links 79-76 are attachedrespectively to a fixed top plate 84 on the anchor 22. The kinematics ofthe chain linkage arrangement permits the lower end of the riser column36 to pivot about two mutually perpendicular horizontal axes, but doesnot permit rotation of the riser column 36 about a vertical axis. Thislatter feature prevents the flexible hoses 46 and 48 from beingsubjected to twist action which, as mentioned previously, can result inshortening the useful life of such hoses. It is to be pointed out thatthe chain linkage arrangement can also be made using a single rigid linkin place of each chain link 62-76, with each rigid link extendingbetween a trunnion pin 58 or 60 and the frame structure 78, or extendingbetween a trunnion pin 80 or 82 and the anchor top plate 84.

The articulate joint 38, with its chain link arrangement thereby allowsthe riser column 36 to pitch and roll in response to wave and currentaction while preventing any significant twisting movement by the risercolumn 36. In this manner, the development of high stresses on themooring terminal 19 is avoided. In this connection, it is noted thatother articulate joint arrangements can also be employed, such as asingle universal joint or a spherical joint designed to provide twodegrees of freedom without twisting. However, one major advantage of thearticulate joint 38 shown and described is that it is not a mechanicaljoint and, therefore, is relatively free from the sealing, corrosion andbearing problems ordinarily accompanying a mechanical joint.

Referring to FIG. 5, there is shown in greater detail the swivelconnection 20 for attaching the mooring line 116 to the anchor 22.Specifically, the lower end 18 of line 116 is fixedly attached to apoint on the ring girder 52 which, in turn, is slidably supported in thefixed bearing frame 54. Frame 54 is affixed to the top of the anchor'22and provides a circular track on which the ring girder 52 travels. Anannular bearing surface is provided along the bearing frame 54 by thrustand radial race pads 86 made of a material, such a phenolic, whichpresents a bearing surface for the ring girder 52 as it rides in acircular path about a vertical axis in response tothe movement of theship 12. Also, stainless steel races 88 are welded to the ring girder 92at locations which cause them to bear on the surfaces of pads 86. Whilethe bearing ring will operate under direct ex-. posure to sea water, itcan be packed in grease and a suitable seal 90 used to prevent waterfrom entering into the bearing areas. The swivel connection 20 isdesigned to provide a high degree of reliability and to operate over along period of time, such as years minimum, without requiringmaintenance.

One possible disadvantage of employing the flexible floating hose 42 asshown in FIG. 1 is that under conditions of ebb or light current thecatenary shape of the mooring line 16 is foreshortened, causing theportion of mooring line 16 near the lower extremity to slacken and lieon the sea bottom 24. Subsequently, as a ship is moored to the terminal10 and changes its position in response to the direction of the currentand/or wind, this lower portion of the mooring line 16 will tend to dragover the sea bottom 24. If the sea bottom 24 provides rough surfaces dueto rock or coral projections, the mooring line 116 may become snagged,and consequently, will not freely follow the traverse of the ship. Inaddition, a rough sea bottom can account for a large portion of wear onthe mooring line. Therefore, it is desirable to maintain the mooringline in a position where it is always clear of the sea bottom 24 and notsubject to abrasion from being dragged thereon and cannot be snagged byprojections on or near the sea bottom 24.

Referring to FIGS. 6 and 7, there is shown a modification of theinvention which includes the use of a rigid boom structure 92 connectedat its inboard end to a rotary joint 94 at the upper end of the risercolumn 36. It is noted that where the parts of the mooring terminalshown in FIG. 6 and 7 are the same as the corresponding parts of themooring terminal 10 shown in FIGS. 1-5, the identical numerals will beused in FIGS. 6 and 7 to identify such parts. The outboard end of theboom 92 includes a connector 96 for joining one or more floating hoses99 and 109 leading to the ship 12. The mooring line catenary 16 isconstituted by a lower portion 161. and an upper portion 16U which aresupported from the boom structure 92 by means of a hanger 102 at theirpoint of juncture. As shown, the boom structure 92 is preferably a spacetruss with the relatively large diameter pipe sections 104 and 106comprising the bottom chord, also serving as conduits for the transferof fluid. As such, the employment of a substantial length of pipesections 1194 and 106 serves to eliminate the need for a substantiallength of relatively costly floating hose. It is to be understood thatthe boom structure 92 can be made of pipes, bars, beams, or combinationsthereof, which form a rigid structure.

The rotary joint 94 comprises a bearing joint which will enable the boom92 to rotate freely about a horizontal axis 106. An additional rotaryjoint 110 permits the boom 92 to freely pivot about the vertical axis112 of the mooring terminal 110. The rotary joint IE0 and swivelconnection 26, respectively, permit the boom 92 and the mooring line 16to freely pivot about the vertical axis 112. The weight of the boom 92and part of the weight of the mooring line 16 are supported by buoyancemeans 114 attached to the boom 92. As noted previously, the auxiliarybuoy 26 supports the upper end of the mooring line 116 and provides anattachment point 30 for the ship's hawser 34.

Ordinarily, when a ship is not connected to the mooring terminal 10 orwhen light current conditions exist, the system will assume aconfiguration as shown in FIG. 8. Here, any slack in the mooring line116 will be taken up by the hanger connection extending down from theboom 92, so that the mooring line 16 does not drop to the sea bottom 24.Alternately, when the ship 12 is attached to the mooring terminal withits tanks connected to the floating hoses 99 and T60, and the currentand wind drag are at the maximum design values, the system will assume aconfiguration as shown in FIG. 6. Therefore, when the ship 12 is notattached to the mooring terminal 10 the equilibrium forces on the boom92 are such that the boom 92 suspends the mooring line 16 above the seabottom 24. Also, it is noted that the floating hoses 96 and 166 willalways tend to float on the sea surface 32.

As an example of the size of the system to which the present inventioncan be designed around, a mooring terminal can be anchored at a IOO-footsea depth with a 100,000 to 300,000 DWT (dead weight ton) ship moored tothis terminal from a distance of over 300 feet. A single mooring line issufficient to accommodate the pitch and heave of the ship withoutdeveloping high dynamic stresses on the line. A 200-foot boom isattached to a pair of 2-foot diameter swivel joints at the upper end ofthe riser column above the surface of the sea. The hoses and fluidconduits deliver oil at the rate of 140,000 barrels per hour.

Although the above description is directed to the preferred embodimentof the invention, it is noted that other variations and modificationswill be apparent to those skilled in the art and, therefore, may be madewithout departing from the spirit and scope of the present disclosure.

What is claimed is:

1. An offshore marine terminal for transferring fluids between a shipand an underwater pipe line comprising:

a. an anchoring structure fastened to the sea floor with a verticalconduit through its in-water section which connects to an underwaterpipeline, and

b. a ring-swivel supported on a bearing around that part of theanchoring structure which extends above the sea bottom, said swivelbeing free to rotate 360 around a vertical axis through the anchoringstructure, and

c. a buoyant riser column connected at its lower end through a joint tothe anchor structure and providing a conduit means through which fluidcan be transferred vertically, said joint between the anchor structureand the riser column acticulated to allow the riser column to pivotabout any horizontal axis at the top of the anchoring structure, and d.a flexible fluid coupling connecting the pipe through the anchorstructure and the conduit in the riser column, and

e. a fluid swivel for the transfer of fluid connected to the upper endof said riser column above the water line for ease of maintenance andprevention of oil leaks, and

f. a rigid boom, hinged at its upper end to the said fluid swivel at thetop end of said riser column, and provided with a buoyancy chamber orchambers at its lower end, and

a howser for holding the ship in place, and a mooring line connected atits lower end to the said ring swivel on the anchor structure andconnected at its upper end to the lower end of said boom and also tosaid hawser which holds the ship in place, and said rigid boom connectedat its lower, buoyant end to the upper end of the mooring line and tothe lower end of the hawser that holds the ship moored, said rigid boomalso carrying a conduit which is in fluid communication with swiveljoint, and

j. a flexible coupling conduit connected between the conduit at thelower end of the rigid boom and the moored ship.

2. Apparatus as recited in claim 1, wherein said articulate jointconnecting said riser column to said anchoring structure includes a pairof trunnion pins connecting the lower end of said riser column to alinkage arrangement attached to said anchoring structure, said linkagearrangement comprising a set of upper links pivotally connected at theirupper ends to said trunnion pins and attached at their lower ends to thefour corners of a rigid frame structure, an additional pair of trunnionpins extending from two opposite sides of said rigid frame structure,and a set of lower links pivotally connected at their upper ends to saidadditional pair of trunnion pins and attached at their lower ends to theanchor structure, whereby said two pairs of trunnion pins are arrangedto provide two mutually perpendicular horizontal axes so that said risercolumn can pivot about said axes.

3. Apparatus as recited in claim 1, wherein said articulate jointcomprises a single universal joint.

4. Apparatus as recited in claim 1, wherein said articulate jointcomprises a spherical ball joint having two degrees of motion, withouttwisting motion.

5. Apparatus as recited in claim 1, wherein there is connected to theupper end of said riser column a floating ring buoy.

6. Apparatus as recited in claim 1, wherein there is provided a buoyancychamber positioned near the upper half of said riser column to maintainsaid riser column in a state of positive buoyancy.

7. Apparatus as recited in claim 1, wherein said fluid swivel couplingmeans omprises a rotary swivel joint at the upper end of said risercolumn, the manifold of said rotary swivel joint communicating with aship-to-riser conduit.

8. Apparatus as recited in claim 1, wherein said second coupling meansfor connecting the lower end of said riser column in fluid communicationwith a submarine pipe line comprises a flexible connection.

9. Apparatus as recited in claim 8, wherein said flexible connectioncomprises a conduit in the lower end of said riser column terminating ina Y-configuration which connects with two flexible hoses, said flexiblehoses being connected at their other ends to a further Y-configurationleading onto said submarine pipe line.

10. Apparatus as recited in claim 9, wherein said riser column isattached at its lower end to said anchoring structure by an articulatejoint to permit said riser column to rotate about two mutuallyperpendicular hori zontal axes while not permitting rotation about avertical axis, thereby preventing said flexible hoses from twistingsubstantially.

11. Apparatus as recited in claim 1, wherein the lower end of saidmooring line is connected to said anchoring means by a swivel connectioncomprising a bearing ring extending around a vertical axis of rotation.

12. Apparatus as recited in claim 11, wherein said swivel connectioncomprises a ring girder slidably supported on bearings in a fixedbearing frame encircling the lower portion of said apparatus andattached to the anchoring structure, whereby movements of said mooringline are accommodated by a swivel motion of said ring girder on itsbearings about a vertical axis.

13. Apparatus as recited in claim 12, wherein said bearings comprisethrust and radial pads attached to said fixed bearing frame, andstainless steel races attached to said ring girder so that saidstainless steel races bear on said pads.

14. Apparatus as recited in claim I, wherein the conduit means for thepassage of fluids between the ship and said first coupling meansincludes a rigid boom structure rotatably connected at its inboard endto the upper end of said riser column for rotation about both ahorizontal and a vertical axis.

15. Apparatus as recited in claim 14, wherein said fluid swivelcomprises a pair of swivel joints having their manifold in fluidcommunication with the conduits in said rigid boom structure, saidswivel joints permitting the boom structure to rotate freely about botha horizontal and a vertical axis.

rigid boom structure and said mooring line are provided with buoyancymeans.

19. Apparatus as recited in claim 18, wherein said buoyancy meansincludes a first buoy connected to the rigid boom structure.

20. Apparatus as recited in claim 19, wherein said buoyancy meansincludes a second buoy attached to the upper end of the mooring line andadapted to also provide an attachment point for the ships hawser.

I k 0 I it

1. An offshore marine terminal for transferring fluids between a shipand an underwater pipe line comprising: a. an anchoring structurefastened to the sea floor with a vertical conduit through its in-watersection which connects to an underwater pipeline, and b. a ring-swivelsupported on a bearing around that part of the anchoring structure whichextends above the sea bottom, said swivel being free to rotate 360*around a vertical axis through the anchoring structure, and c. a buoyantriser column connected at its lower end through a joint to the anchorstructure and providing a conduit means through which fluid can betransferred vertically, said joint between the anchor structure and theriser column acticulated to allow the riser column to pivot about anyhorizontal axis at the top of the anchoring structure, and d. a flexiblefluid coupling connecting the pipe through the anchor structure and theconduit in the riser column, and e. a fluid swivel for the transfer offluid connected to the upper end of said riser column above the waterline for ease of maintenance and prevention of oil leaks, and f. a rigidboom, hinged at its upper end to the said fluid swivel at the top end ofsaid riser column, and Provided with a buoyancy chamber or chambers atits lower end, and g. a howser for holding the ship in place, and h. amooring line connected at its lower end to the said ring swivel on theanchor structure and connected at its upper end to the lower end of saidboom and also to said hawser which holds the ship in place, and i. saidrigid boom connected at its lower, buoyant end to the upper end of themooring line and to the lower end of the hawser that holds the shipmoored, said rigid boom also carrying a conduit which is in fluidcommunication with swivel joint, and j. a flexible coupling conduitconnected between the conduit at the lower end of the rigid boom and themoored ship.
 2. Apparatus as recited in claim 1, wherein said articulatejoint connecting said riser column to said anchoring structure includesa pair of trunnion pins connecting the lower end of said riser column toa linkage arrangement attached to said anchoring structure, said linkagearrangement comprising a set of upper links pivotally connected at theirupper ends to said trunnion pins and attached at their lower ends to thefour corners of a rigid frame structure, an additional pair of trunnionpins extending from two opposite sides of said rigid frame structure,and a set of lower links pivotally connected at their upper ends to saidadditional pair of trunnion pins and attached at their lower ends to theanchor structure, whereby said two pairs of trunnion pins are arrangedto provide two mutually perpendicular horizontal axes so that said risercolumn can pivot about said axes.
 3. Apparatus as recited in claim 1,wherein said articulate joint comprises a single universal joint. 4.Apparatus as recited in claim 1, wherein said articulate joint comprisesa spherical ball joint having two degrees of motion, without twistingmotion.
 5. Apparatus as recited in claim 1, wherein there is connectedto the upper end of said riser column a floating ring buoy.
 6. Apparatusas recited in claim 1, wherein there is provided a buoyancy chamberpositioned near the upper half of said riser column to maintain saidriser column in a state of positive buoyancy.
 7. Apparatus as recited inclaim 1, wherein said fluid swivel coupling means omprises a rotaryswivel joint at the upper end of said riser column, the manifold of saidrotary swivel joint communicating with a ship-to-riser conduit. 8.Apparatus as recited in claim 1, wherein said second coupling means forconnecting the lower end of said riser column in fluid communicationwith a submarine pipe line comprises a flexible connection.
 9. Apparatusas recited in claim 8, wherein said flexible connection comprises aconduit in the lower end of said riser column terminating in aY-configuration which connects with two flexible hoses, said flexiblehoses being connected at their other ends to a further Y-configurationleading onto said submarine pipe line.
 10. Apparatus as recited in claim9, wherein said riser column is attached at its lower end to saidanchoring structure by an articulate joint to permit said riser columnto rotate about two mutually perpendicular horizontal axes while notpermitting rotation about a vertical axis, thereby preventing saidflexible hoses from twisting substantially.
 11. Apparatus as recited inclaim 1, wherein the lower end of said mooring line is connected to saidanchoring means by a swivel connection comprising a bearing ringextending around a vertical axis of rotation.
 12. Apparatus as recitedin claim 11, wherein said swivel connection comprises a ring girderslidably supported on bearings in a fixed bearing frame encircling thelower portion of said apparatus and attached to the anchoring structure,whereby movements of said mooring line are accommodated by a swivelmotion of said ring girder on its bearings about a vertical axis. 13.Apparatus as recited in claim 12, wherein said bearings comprise thrustand radial pads attached to said fixed bearing frame, and stainlesssteel races attached to said ring girder so that said stainless steelraces bear on said pads.
 14. Apparatus as recited in claim 1, whereinthe conduit means for the passage of fluids between the ship and saidfirst coupling means includes a rigid boom structure rotatably connectedat its inboard end to the upper end of said riser column for rotationabout both a horizontal and a vertical axis.
 15. Apparatus as recited inclaim 14, wherein said fluid swivel comprises a pair of swivel jointshaving their manifold in fluid communication with the conduits in saidrigid boom structure, said swivel joints permitting the boom structureto rotate freely about both a horizontal and a vertical axis. 16.Apparatus as recited in claim 14, wherein said mooring line includes anupper length of line and a lower length of line, with the point betweensaid upper and said lower lengths being connected to said rigid boomstructure to provide a support for said mooring line.
 17. Apparatus asrecited in claim 14, wherein said rigid boom structure is a space trussincluding tubular members as said conduit means.
 18. Apparatus asrecited in claim 14, wherein said rigid boom structure and said mooringline are provided with buoyancy means.
 19. Apparatus as recited in claim18, wherein said buoyancy means includes a first buoy connected to therigid boom structure.
 20. Apparatus as recited in claim 19, wherein saidbuoyancy means includes a second buoy attached to the upper end of themooring line and adapted to also provide an attachment point for theship''s hawser.